Stimulus-specific adaptation in the medial geniculate body of the rat
-
1
Auditory Neurophysiology Unit, Institute for neuroscience of Castilla y Leon, Spain
-
2
Department of Psychology, University of Washington, United States
Novelty detection has been extensively studied using the non-invasive technique of recording mismatch negativity (MMN) (Näätänen 1992). However, the identity and location of the cortical neuronal generator of the MMN is still unknown, and there is a lack of knowledge about novelty processing at subcortical levels. In a dynamic environment, animals are able to continuously modulate the state of their auditory system, enabling them to rapidly distinguish what is novel from what is familiar. This would likely be reflected in neuronal firing patterns changes of some neurons if they are involved in detecting novel sounds. Neural adaptation is a ubiquitous process in biological systems and it is well known to occur in various forms in the auditory system. However, Ulanovsky and colleagues (2003, 2004) were the first to describe a particular form of adaptation in the cat auditory cortex, referred to as stimulus-specific adaptation (SSA). This form of adaptation shares some similarities with the MMN in humans and therefore has been proposed as a single neuron correlate of this phenomenon. Stimulus-specific adapting neurons show a reduced response to a repeated stimulus (standard), and briefly resume firing if a novel stimulus (oddball) is presented. SSA is not a unique property of auditory cortex neurons. It also occurs in neurons at the midbrain level, in the inferior colliculus (IC) of the rat (Perez-Gonzalez 2005; Malmierca et al. 2009). Since both the IC and the AC contain neurons that exhibit SSA, one would expect MGB neurons to inherit this property from the AC, the IC or both. Nevertheless, to date, no study has demonstrated that MGB neurons show SSA. To examine this issue we used a protocol similar to that of Ulanovsky et al. (2003) while recording extracellular single unit responses in the MGB of the anesthetized rat. Our data demonstrates that SSA is indeed present throughout the MGB of the rat, being more prominent in the dorsal and medial subdivisions, suggesting the involvement of the paralemniscal auditory pathway. It remains unclear if SSA in MGB neurons is due to thalamic processing or if it reflects processing that has already occurred in the IC or AC. We hypothesize that SSA may be shaped, at least in part, through a bottom-up process.
Supported by Spanish MEC (BFU2006-00572) and JCYL (GR221) to MSM, NSF grant (IOS-0719295) to EC and MEC fellowship (BES-2007-15642) to FMA.
Conference:
MMN 09
Fifth Conference on Mismatch Negativity (MMN) and its Clinical and Scientific Applications, Budapest, Hungary, 4 Apr - 7 Apr, 2009.
Presentation Type:
Poster Presentation
Topic:
Poster Presentations
Citation:
Antunes
F,
Covey
E and
Malmierca
MS
(2009). Stimulus-specific adaptation in the medial geniculate body of the rat.
Conference Abstract:
MMN 09
Fifth Conference on Mismatch Negativity (MMN) and its Clinical and Scientific Applications.
doi: 10.3389/conf.neuro.09.2009.05.144
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
26 Mar 2009;
Published Online:
26 Mar 2009.
*
Correspondence:
Flora Antunes, Auditory Neurophysiology Unit, Institute for neuroscience of Castilla y Leon, Salamanca, Spain, antunes.flora.m@gmail.com